Bell hammer driving device for alarm mechanism



Oct. 21, 1969 3,473,507

BELL HAMMER DRIVING DEVICE FOR ALARM MECHANISM JEAN-CLAUDE SCHNEIDER 2 Sheets-Sheet 1 Filed Dec.

N MEN .5 Q 8 mm 1969 JEAN-CLAUDE SCHNEIDER 3,473,507

BELL HAMMER DRIVING DEVICE FOR ALARM MECHANISM Filed Dec. 235, 1966 2 Sheets-Sheet 2 EYE. Z

United States Patent Ofice 3,473,507 Patented Oct. 21, 1969 US. Cl. 116-149 7 Claims ABSTRACT OF THE DISCLOSURE An alarm bell ringing mechanism adapted to ring a bell at successively varying rates.

The present invention is directed to a bell hammer driving device for alarm mechanisms, for example, alarm clocks, wherein the bell ringing frequency varies during successive bell ringing intervals.

A distinguishing feature of the aforementioned device is that a means is provided for oscillatingly pivoting a bell striking hammer through successive pivot angles which vary as to amplitude whereby said hammer strikes the bell either once or twice for each complete oscillation, depending upon the amplitude of the pivot angle. Specifically, when the oscillatory amplitude, that is the pivot angle, is of a lower value, the hammer strikes the bell only once, at one end of the oscillatory stroke, while when the pivot angle is of a higher value the hammer strikes the bell twice, one time at each end of the oscillatory stroke.

The objects of the present invention are to provide a hammer driving device of the aforementioned type and to provide such a device through a structural combination of parts which results in a simple, easy to construct, economical, and highly reliable device.

Specific objects of the present invention will be evident from the following detailed description of a preferred embodiment which is referred to the accompanying drawings, wherein:

FIGURE 1 is a partial sectional view of a clock movement including the device of this invention; and

FIGURE 2 is a plan view of one of the novel members of the device which is included in FIGURE 1.

In FIGURE 1, reference numerals and 6 denote parallel, spaced apart frame elements of a clock movement, between which various moving parts of the movement are mounted. The frame elements 5 and 6 commonly extend in vertical planes since, as is well known, clocks usually stand upright; therefore, normally all pivot axes which extend perpendicular to elements 5 and 6 will extend horizontally.

The hammer 1 is rigid with shaft 2 whose stem 3 is pivotally supported in bore 4 in the element 5. An axially extending boss 7, integral with opposite frame element 6, serves as a stop to prevent axial displacement of hammer 1. The not shown portion of hammer 1, which extends towards the right in FIGURE 1,- is arranged to strike a not shown bell. The left portion of hammer 1 includes an axially extending rigid pin 8 which is drivingly engaged with hammer drive lever 9 which, in turn, is pivotally supported between the frame elements 5 and 6 by means of respective stems 10 and 11, the latter stem being supported in bore 12 in boss 13 rigidly extending from frame element 6. It is evident, therefore, that pivoting of lever 9 about the axis of stems 10 and 11 results in pivoting of hammer 1 through the driving engagement between lever 9 and pin 8.

Lever 9 is itself driven by an escape wheel 14 through a known type of driving connection therewith. Escape wheel 14 is pivotally mounted between the frame elements :by means of stem 15 which extends from boss 16 which, in turn, extends from element 5. A pinion 17 is pivotally mounted on and coaxially with wheel 14 by means of stem 18 which extends into bore 19 in boss 20 rigid with frame element 6, land 'by means of a bored portion 36 which is pivotally mounted about a central boss 37 on wheel 14. Pinion 17 and wheel 14 are drivingly interconnected with each other through a Breguet toothing 23 whereby pinion 17 can turn in one direction without driving wheel 14 while turning of pinion 17 in the opposite direction results in wheel 14 being driven thereby. Pinion 17 is urged axially towards wheel 14 so as to maintain the necessary engagement in the Breguet toothing, by compression spring 21 which is wound about a cylindrical portion of boss 20, said spring being compressed between shoulder 22 at the upper end of said cylindrical portion and an opposite shoulder on pinion 17.

Axially extending circum'ferentially spaced studs 24 on Wheel 14 and located radially outwardly of pinion 17, serve, in conjunction with a not shown :blocking device, such as that shown in US. Patent No. 3,316,707, to block the wheel 14 against any rotation during certain periods. Since the aforementioned blocking device is not essential to an understanding of this invention, it is not necessary to describe it further.

Pinion 17 is itself driven by a toothed runner 25 which, in turn, is powered by an energy means comprising an alarm coil spring 28. The outer end of coil spring 28 is fixedly attached to the side surface 29 of boss 20 while its inner end is attached to the outer surface of collar 27 which is a rigid part of runner 25. The shaft portion 27' of the runner 25 extends outwardly of frame element 6 to a not shown winding means, such as that shown in US. Patent No. 360,346, through which runner 25 may be turned so as to wind spring 28. Runner 25 is pivotally mounted between frame elements 5 and 6 by means of shaft 27' and by means of stem 26 which extends into a bore 38 in a frame part.

Runner 25 includes a rim portion 39 along whose outer circumferential surface there is formed a driver toothing comprised of four successive sectors 30-33 (-FIGURE 2). Sectors 31 and 33 are approximately the same length and are positioned approximately diametrically opposite to each other as are sectors 30 and 32 which, however, are of substantially different lengths. In FIGURE 2, it is seen that sectors 30 and 32 are set radially inward from sectors 31 and 33, while in FIGURE 1, it is seen that sectors 30 and 32 are in a different axial plane from sectors 31 and 33.

The respective pairs of sectors 31, 33 and 30, 32 are in driving engagement with axially adjacent toothings 34 and 35, respectively, on pinion 17, the diameters of which are different in accordance with the different diameters of the respective pairs of sectors. Toothings 34 and 35, however, each have the same number of teeth so that, therefore, the pitch between teeth on toothing 34 is different from that on toothing 35. correspondingly, the teeth pitch on sectors 31 and 33 is the same as that of toothing 34 while that of sectors 30 and 32 is the same as that of toothing 35.

The operation of the disclosed device is as follows.

Primarily, runner 25 can be turned by means of the not shown winding means attached to shaft 27' in order to wind power spring 28 to store energy therein. During such winding, wheel 14 will be blocked by the not shown blocking means engaging studs 24, and pinion 17 will simply turn in the free turning direction permitted by the Breguet toothing 23 which comprises a unidirectional drive means from wheel 14 to pinion 17. When the winding is completed, spring 28 will remain wound so long as wheel 14 is blocked because the Breguet toothing 23 will not permit spring 28 to drive runner 25 in the unwinding direction. {When it is time to ring the alarm bell, the wheel 14 becomes unblocked and thereby energy means 28 drives runner 25 in a direction opposite to the aforementioned winding direction, which drives pinion 17, which drives wheel 14, and which, in turn, drives lever 9 and hammer 1, the elements 25, 17, and 14 constituting part of a transmission means connecting the energy means 28 to the driven members 9 and 1.

During a complete rotation of runner 25, pinion 17 is successively driven by driver toothing sectors 30, 31, 32, and 33 which alternately engage toothings 34 and 35 on said pinion. In this regard, it should be noted that lever 9 serves to maintain the rotational speed of wheel 14, and through it pinion 17, at approximately constant value so that under the influence of the Spring 28 it is the runner 25 which turns at a variable speed.

The result is that the lever 9 is driven with a varying degree of energy depending upon whether either of sectors 30 and 32, or sectors 31 and 33 is driving the pinion 17, the greater driving energy being imparted by sectors 30 and 32. The driving energy is determined by the amount of torque exerted by spring 28 through runner 25 to pinion 17, and by the angle through which runner 25 turns for each pivoting stroke of lever 9. This angle is greatest when the ratio between the respective toothings on the runner 25 and on the pinion 17 is smallest, and the energy imparted to lever 9 is correspondingly greater during this condition and the lever 9, therefore, is pivoted through a greater pivot angle. The not shown right hand end of hammer 1 strikes the not shown bell at each end of its pivot stroke when the oscillatory amplitude of lever 9 is greatest but only at the end of the stroke when the oscillatory amplitude is of the lower value. Specifically, when sectors 30 or 32 are in engagement with toothing 35, the bell ringing rate is twice that which it is when the sectors 31 or 33 are in engagement with toothing 34. Actually, the bell ringing rate ratio in practice is greater than two to one because the second ringing of the bell during each double ringing stroke slightly tends to accelerate the oscillations of lever 9. Lever, 9, therefore, comprises an adjustment means for maintaining the speed of the transmission means wheel 14 constant.

The runner 25 is intended to be incorporated in an alarm mechanism in which the ringing takes place in two periods separated by a period of time which may be adjusted to between several minutes and several hours. Each ringing period starts with an orientation of the runner 26 such that the start of the sector 31 or the start of the sector 33 is opposite the pinion 17. Each period of ringing, therefore, starts with slow rate and then continues with rapid rate. Of course, the toothings of the runner 25 could also be arranged and distributed differently. This runner could have only a single sector of toothing of large diameter and a sector of toothing of small diameter.

The runner 25, as well as the pinion 17, are conveniently made of plastic. As the toothings 34 and 35 have the same number of teeth, the manufacture of this pinion does not present any difliculties. The same is true of the toothings of the runner 25 since the toothings do not overlap at any time.

These toothings can, therefore, be made with all desired precision in an injection mold of ordinary design.

In other embodiments, one could also use other means for varying, during the ringing, the amplitude of the oscillations of the hammer 1 so that the hammer strikes the bell at each end of its stroke.

The foregoing details of a preferred embodiment of realization of the invention are for illustrative and not limitative purposes, it being understood that the invention is intended to cover all modifications, substituitons, or equivalents which are either obvious or well within the purview of one skilled in the art.

What is claimed is:

1. An alarm bell ringing mechanism comprising: a bell ringing hammer, a drive lever for driving said hammer, an energy means for driving said lever, a transmission means connecting said energy means with said lever, said transmission means being adapted to drive said lever with alternately varying amounts of energy, said hammer being adapted to strike a bell at a varying rate in accordance with the varying amount of driving energy imparted to said lever, said energy means providing a substantially constant value of torque to said transmission means, adjustment means maintaining said transmission means at a substantially constant speed under the driving action of said torque, said transmission means comprising a driven toothing means and said energy means comprising a driver toothing means engageable with said driven toothing means, means to alternately vary the gear ratio between said driver and driven toothing means, said transmission means comprising an escapement wheel driven toothing means, said escapement wheel being drivingly associated with one end of said drive lever, said drive lever being pivoted intermediate its ends, said hammer comprising an arm pivoted intermediate its ends, the other end of said drive lever being drivingly associated with one end of said hammer arm, the other end of said hammer arm being adapted to strike an alarm bell.

2. The mechanism of claim 1, said escapement wheel being driven by said driven toothing means through a unidirectional drive means.

3. The mechanism of claim 2, said energy means comprising a rotatable runner having said driver toothing means thereon, a windable spring drivingly associated with said runner for rotating same in one driving direction, said runner being rotatable in an opposite direction to Wind said spring.

4. An alarm bell ringing mechanism comprising: a bell ringing hammer, a drive lever for driving said hammer, an energy means for driving said lever, a transmission means connecting said energy means with said lever, said transmission means being adapted to drive said lever with alternately varying amounts of energy, said ham rner being adapted to strike a bell at a varying rate in accordance with the varying amount of driving energy imparted to said lever, said energy means providing a substantially constant value of torque to said transmission means, adjustment means maintaining said transmission means at a substantially constant speed under the driving action of said torque, said transmission means comprising a rotatable pinion having two toothed portions at different axial levels thereon, said energy means comprising a rotatable runner having a toothed surface delined by circumferentially successive sectors axially displaced from one another, said successive sectors engaging respective ones of said toothed pinion portions, the gear ratios between the respective interengaging toothings being different from each other.

5. The mechanism of claim 4, said pinion toothed portions having different pitch diameters relative to each other, and said runner toothed sectors having correspondingly different pitch diameters relative to each other.

'6. The mechanism of claim 4, said runner toothed surface being defined by four of said sectors, a first pair of said sectors being located in a first axial plane and a second pair of said sectors being located in a second axial plane, the sectors in each pair successively following a sector of the other pair in a circumferential direction.

7. The mechanism of claim 4, said runner sectors being of different circumferential lengths.

References Cited UNITED STATES PATENTS DANIEL M. YASICH, Assistant Examiner US. Cl. X.R. 

